// 兼容
window.URL = window.URL || window.webkitURL
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia || navigator.msGetUserMedia
let HZRecorder = function (stream, config) {
 config = config || {}
 config.sampleBits = config.sampleBits || 8 // 采样数位 8, 16
 config.sampleRate = config.sampleRate || (44100 / 8) // 采样率(1/6 44100)
 let context = new (window.webkitAudioContext || window.AudioContext)()
 let audioInput = context.createMediaStreamSource(stream)
 let createScript = context.createScriptProcessor || context.createJavaScriptNode
 let recorder = createScript.apply(context, [16384, 1, 1])
 let audioData = {
  size: 0, // 录音文件长度
  buffer: [], // 录音缓存
  inputSampleRate: context.sampleRate, // 输入采样率
  inputSampleBits:  config.sampleBits || 16,
  outputSampleRate: config.sampleRate, // 输出采样率
  oututSampleBits: config.sampleBits, // 输出采样数位 8, 16
  input: function (data) {
   this.buffer.push(new Float32Array(data))
   this.size += data.length
  },
  compress: function () { // 合并压缩
   // 合并
   let data = new Float32Array(this.size)
   let offset = 0
   for (let i = 0; i < this.buffer.length; i++) {
    data.set(this.buffer[i], offset)
    offset += this.buffer[i].length
   }
   // 压缩
   let compression = parseInt(this.inputSampleRate / this.outputSampleRate)
   let length = data.length / compression
   let result = new Float32Array(length)
   let index = 0; let j = 0
   while (index < length) {
    result[index] = data[j]
    j += compression
    index++
   }
   return result
  },
  encodeWAV: function () {
   let sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate)
   let sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits)
   let bytes = this.compress()
   let dataLength = bytes.length * (sampleBits / 8)
   let buffer = new ArrayBuffer(44 + dataLength)
   let data = new DataView(buffer)
   let channelCount = 1// 单声道
   let offset = 0
   let writeString = function (str) {
    for (let i = 0; i < str.length; i++) {
     data.setUint8(offset + i, str.charCodeAt(i))
    }
   }
   // 资源交换文件标识符
   writeString('RIFF'); offset += 4
   // 下个地址开始到文件尾总字节数,即文件大小-8
   data.setUint32(offset, 36 + dataLength, true); offset += 4
   // WAV文件标志
   writeString('WAVE'); offset += 4
   // 波形格式标志
   writeString('fmt '); offset += 4
   // 过滤字节,一般为 0x10 = 16
   data.setUint32(offset, 16, true); offset += 4
   // 格式类别 (PCM形式采样数据)
   data.setUint16(offset, 1, true); offset += 2
   // 通道数
   data.setUint16(offset, channelCount, true); offset += 2
   // 采样率,每秒样本数,表示每个通道的播放速度
   data.setUint32(offset, sampleRate, true); offset += 4
   // 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8
   data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true); offset += 4
   // 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8
   data.setUint16(offset, channelCount * (sampleBits / 8), true); offset += 2
   // 每样本数据位数
   data.setUint16(offset, sampleBits, true); offset += 2
   // 数据标识符
   writeString('data'); offset += 4
   // 采样数据总数,即数据总大小-44
   data.setUint32(offset, dataLength, true); offset += 4
   // 写入采样数据
   if (sampleBits === 8) {
    for (let i = 0; i < bytes.length; i++ , offset++) {
     let s = Math.max(-1, Math.min(1, bytes[i]))
     let val = s < 0 ? s * 0x8000 : s * 0x7FFF
     val = parseInt(255 / (65535 / (val + 32768)))
     data.setInt8(offset, val, true)
    }
   } else {
    for (let i = 0; i < bytes.length; i++ , offset += 2) {
     let s = Math.max(-1, Math.min(1, bytes[i]))
     data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true)
    }
   }
   return new Blob([data], { type: 'audio/wav' })
  }
 }
 // 开始录音
 this.start = function () {
  audioInput.connect(recorder)
  recorder.connect(context.destination)
 }
 // 停止
 this.stop = function () {
  recorder.disconnect()
 }
 // 获取音频文件
 this.getBlob = function () {
  this.stop()
  return audioData.encodeWAV()
 }
 // 回放
 this.play = function (audio) {
  let downRec = document.getElementById('downloadRec')
  downRec.href = window.URL.createObjectURL(this.getBlob())
  downRec.download = new Date().toLocaleString() + '.mp3'
  audio.src = window.URL.createObjectURL(this.getBlob())
 }
 // 上传
 this.upload = function (url, callback) {
  let fd = new FormData()
  fd.append('audioData', this.getBlob())
  let xhr = new XMLHttpRequest()
  /* eslint-disable */
  if (callback) {
   xhr.upload.addEventListener('progress', function (e) {
    callback('uploading', e)
   }, false)
   xhr.addEventListener('load', function (e) {
    callback('ok', e)
   }, false)
   xhr.addEventListener('error', function (e) {
    callback('error', e)
   }, false)
   xhr.addEventListener('abort', function (e) {
    callback('cancel', e)
   }, false)
  }
  /* eslint-disable */
  xhr.open('POST', url)
  xhr.send(fd)
 }
 // 音频采集
 recorder.onaudioprocess = function (e) {
  audioData.input(e.inputBuffer.getChannelData(0))
  // record(e.inputBuffer.getChannelData(0));
 }
}
// 抛出异常
HZRecorder.throwError = function (message) {
 alert(message)
 throw new function () { this.toString = function () { return message } }()
}
// 是否支持录音
HZRecorder.canRecording = (navigator.getUserMedia != null)
// 获取录音机
HZRecorder.get = function (callback, config) {
 if (callback) {
  if (navigator.getUserMedia) {
   navigator.getUserMedia(
    { audio: true } // 只启用音频
    , function (stream) {
     let rec = new HZRecorder(stream, config)
     callback(rec)
    }
    , function (error) {
     switch (error.code || error.name) {
      case 'PERMISSION_DENIED':
      case 'PermissionDeniedError':
       HZRecorder.throwError('用户拒绝提供信息。')
       break
      case 'NOT_SUPPORTED_ERROR':
      case 'NotSupportedError':
       HZRecorder.throwError('浏览器不支持硬件设备。')
       break
      case 'MANDATORY_UNSATISFIED_ERROR':
      case 'MandatoryUnsatisfiedError':
       HZRecorder.throwError('无法发现指定的硬件设备。')
       break
      default:
       HZRecorder.throwError('无法打开麦克风。异常信息:' + (error.code || error.name))
       break
     }
    })
  } else {
   HZRecorder.throwErr('当前浏览器不支持录音功能。'); return
  }
 }
}
export default HZRecorder